Which of the following is true for all types of leucocytes?

Options

A. There are nucleated and long lived
B. There are colourless and relatively more in number
C. These are granulated and phagocytic
D. These are nucleated and generally short lived

Answer

To determine which statement is true for all types of leucocytes, we need to analyze the characteristics of leucocytes (white blood cells) and compare them with the options provided.

### Step-by-Step Solution:

1. **Understanding Leucocytes**:
- Leucocytes are the white blood cells in the body that play a crucial role in the immune system. They are involved in protecting the body against infections and foreign invaders.

2. **Characteristics of Leucocytes**:
- **Nucleated**: All leucocytes have a nucleus, which is a defining characteristic that differentiates them from red blood cells (erythrocytes) that lack a nucleus.
- **Lifespan**: Leucocytes generally have a shorter lifespan compared to red blood cells. They typically live for about 15 to 20 days.
- **Colorless**: Leucocytes are colorless, which is true for all types.
- **Granulated vs. Agranulated**: Leucocytes can be classified into two categories:
- Granulated (e.g., neutrophils, eosinophils, basophils) which have granules in their cytoplasm.
- Agranulated (e.g., lymphocytes, monocytes) which do not have granules.

3. **Evaluating the Options**:
- **Option 1**: "They are nucleated and long-lived."
- Nucleated is correct, but long-lived is incorrect. This option is false.
- **Option 2**: "They are colorless and relatively more in number."
- Colorless is correct, but they are not relatively more in number compared to red blood cells. This option is false.
- **Option 3**: "They are granulated and phagocytic."
- Some leucocytes are granulated, but not all. While phagocytosis is a function of some leucocytes, it does not apply to all types. This option is false.
- **Option 4**: "They are nucleated and generally short-lived."
- Both characteristics are true for all types of leucocytes. This option is correct.

4. **Conclusion**:
- The correct answer is **Option 4: "They are nucleated and generally short-lived."**